Cell Biology Quiz

Exam Final 2024 Topics

• Plasma Membrane: A phospholipid bilayer with embedded proteins. It regulates what enters and leaves the cell. Includes components like lysosomes, peroxisomes, rough and smooth endoplasmic reticulum, centrioles, cilia, centrosome, cytoplasm, microvilli, mitochondrion, ribosomes, nucleoplasm, nucleolus, nuclear pores, and nuclear envelope.

Golgi Apparatus

• Structure: A series of flattened sacs (cisternae) with associated vesicles. Has distinct cis (forming) and trans (maturing) faces. Also has associated tubules.
• Functions: Glycosylation of proteins and lipids, protein modification, and packaging of secreted proteins into vesicles.

Cytoskeleton

• Actin Filaments (Microfilaments): Two-stranded helical polymers. Found in the cell cortex and involved in cell motility and contractility.
• Microtubules: Long hollow cylinders made of tubulin protein. Crucial for intracellular transport, cilia, and flagella.
• Intermediate Filaments: Rope-like fibers, composed of various intermediate filament proteins. Provide strength and mechanical support to cells. Keratin forms a large part of these fibers.

Extracellular Matrix (ECM)

• Composition: Composed of fibrous proteins (e.g., collagen, fibronectin), proteoglycans, and adhesive glycoproteins.
• Function: Provides structural support, regulates cell signaling and binds cells together.

Stem Cell/Apoptosis (Cell Birth, Lineage and Death)

• Stem Cells: Unspecialized cells that can self-renew and differentiate into specialized cell types.
• Apoptosis: Programmed cell death, a crucial process for tissue development and maintenance. Necrosis is the opposite, rapid lysis of the cell.
• Lineage: Series of cell divisions from stem cells to differentiated cells; there are distinct stages in this process.

Membrane Proteins

• Transmembrane Proteins: Proteins that span the membrane and mediate transport of substance. Examples include: ion channels, integrin dimers and Glycoproteins
• Peripheral Proteins: Proteins that sit on one side of the membrane interacting with membrane components indirectly only.

Chemical Basics

• Polar molecules: Soluble in polar solvents like water.
• Nonpolar molecules: Insoluble in water; aggregate together.

Phospholipids

• Amphipathic: Both polar and nonpolar regions

Fatty acids

• Saturated: No double bonds.
• Unsaturated: At least one double bond.

Other Components of Membranes

• Glycoproteins: Carbohydrates attached to proteins, increasing their hydrophilicity and stabilizing their conformation in the membrane.

• Glucolipids (Glycolipids): Carbohydrates attached to lipids, increasing their hydrophilicity.

Types of Membrane Proteins

• Integral (Transmembrane): Domains that cross the membrane; mostly alpha helices or beta sheets.

• Peripheral: Associated with one side of the membrane; may attach to membrane components.

Steroids

• Typical example is Cholesterol.
• They are amphipathic, with a hydrophilic region and a hydrophobic region.

Protein Classification (A.A)

• Nonpolar R groups: Hydrophobic
• Polar R groups: Hydrophilic
• Negatively Charged R groups: Hydrophilic
• Positively charged R groups: Hydrophilic

Erythrocyte Membrane

• Key structural proteins: Spectrin, Ankyrin, Actin, Tropomyosin, and Adducin, etc.

Bacteriodopsin and Porins

• Porins: Transmembrane proteins forming barrels that facilitate the passage of disaccharides and phosphates across the membrane.
• Bacteriodopsin: Contains multiple alpha-helices that cross the membrane; transmembrane protein.

Immunofluorescence (locating proteins inside the cell)

• Method to visualize proteins inside a living sample. Includes direct and indirect immunofluorescence.

Centrifugation Techniques

• Differential centrifugation: Separates cellular components based on size and density.
• Rate zonal centrifugation: Separates components based on density in a density gradient.

SDS-polyacrylamide Gel Electrophoresis (SDS-PAGE)

• Separates proteins based on size.

Estimating Protein Molecular Weight

• Using known molecular weight standards, plotting a graph of logarithm of molecular weight against relative migration allows estimating the unknown protein molecular weight.

Gel Filtration Chromatography

• Separates proteins based on size (large molecules elute first).
• Separates based on molecular size of protein.
• Separates by molecular size during the experiment

Antibody techniques

• ELISA: Method for detecting and quantifying a specific protein using antibodies.

• Western Blot: Method for detecting a specific protein using antibodies that detects a target protein of interest.

Immune response to blood groups

• Antigens and Antibodies. The specific reactions between them result in different blood types.
• Different blood groups based on their carbohydrate antigens.

Glycosylation

• Modifications of glycoproteins by carbohydrates in the endoplasmic reticulum and Golgi complex, which are important for stability and folding of proteins.

Processing of N-linked oligosaccharide chains

• Steps in enzymatic processes for modifying proteins using carbohydrates and their precursors

Modifications of N-oligosaccharides

• Localization of enzymes responsible for modifying N-oligosaccharides in the Golgi complex.

Structure of Axonemes of Cilia and Flagella

• Structure: Provides a basic picture demonstrating the different components of cilia and flagella to help understand their functions.

Dynein and Kinesin (Microtubule associated proteins) , Motor Proteins

• Kinesins: Motor proteins that move along microtubules towards the plus (+) end. Involved in anterograde transport (towards the cell periphery).
• Dyneins: Motor proteins that move along microtubules towards the minus (-) end. Involved in retrograde transport (toward the cell body) in vesicular traffic, ciliary muscles and cellular movements.
• Basic Structure of both proteins, particularly describing head, tails, and other structural regions associated with the proteins

Intermediate filaments

• Keratin and its involvement with the process of skin diseases (Epidermolysis bullosa simplex)
• Structural and other important characteristics(properties) of intermediate filaments.

Cytoskeleton II

• Microtubules, their role in intracellular transport through cilia and flagella, and their structure (tubulin protein forming hollow cylinders) along with basic functions. MTOC (Microtubules-Organizing Center) also known as the centrioles (pair of centrioles forming a structure that looks like a perpendicular 'L').

Dynamic Instability

• Dynamic instability (growth and shrinkage): property of microtubules, with processes of catastrophe and rescue.

Polarization of Epithelial Cells:

• Process by which epithelial cells develop a polarized structure, including apical and basement membrane (basolateral).

Mechanotransduction:

• The process in which physical forces applied to a cell translate into intracellular signalling pathways and cellular responses. How mechanical stress is communicated to the internal cell.

Golgi Apparatus

• Cis face: The receiving face/entry point of the Golgi.
• Trans face: The shipping/destination region of the Golgi.

Peroxisome

• Import system: Includes Pex proteins that direct proteins into peroxisomes.

Mannose-6-Phosphate (M6P)

• Targeting sequence: Directs enzymes to lysosomes through binding to M6P receptors.

Other routes of M6P

• Receptor-mediated endocytosis: How cells bring M6P-tagged proteins into the lysosomes, including the role of receptors, vesicles, clathrin, etc.

Proteoglycans

• Composition: Multiple glycosaminoglycans linked to a core protein. Form a network in cartilage, etc.

Fibronectin

• Structure and Function.

Collagen

• Composition, including the triple helix and its importance in the extra-cellular matrix.
• Molecular structure of collagen type IV (basal lamina)

Cell Birth, Lineage, and Death

• Overview of cell birth from symmetric and asymmetric cell divisions, and how these processes influence cell lineages.

Apoptosis

• Morphological changes and role of proteins during the process of apoptosis.

Test your knowledge on key concepts in cell biology, including the functions and structures of proteins, organelles, and cellular processes. Explore the roles of transmembrane proteins, the Golgi apparatus, and the mechanics of motor proteins like kinesin and dyneins.